Estimation of the Maintenance Energy Requirements of Beef Cattle and Lambs

Abstract

The maintenance energy requirement of an animal can be defined as the daily metabolisable energy (ME) intake at which it is in zero energy balance. Maintenance energy requirements can be estimated either by measuring fasting metabolism or from a regression relationship between ME intake and energy retention for a number of animals given a range of ME intakes. However maintenance energy requirements may vary according to the composition of the diet, as higher intakes of high-fibre diets have promoted greater rates of gut metabolism than lower intakes of low-fibre diets. In the present study maintenance energy requirements of beef cattle and lambs have been estimated by regressions between ME intake and energy retention using data from a series of studies involving diets based on grass silage or fresh grass and concentrates.